Component Replacement Instructions
505i
Remove Heat Exchanger and Air Intake/Exhaust
20. Remove 8 screws connecting the assembly to the water heater casing assembly. (Figures 61, 62)
Separate the Heat Exchanger from the Air Intake/Exhaust
21. Pull out the assembly. Remove 3 brackets on the side and back holding the fusible link.
22. Remove the 9 screws at the cover plate over the air intake passage. (Figure 63)
23. Remove the 4 screws attaching the heat exchanger to the air intake/exhaust assembly. (Figure 64)
24. Pull apart the heat exchanger and air intake/exhaust assembly. (Figure 65)
25. Remove 4 screws attaching the bracket on top of the heat exchanger. Pull off the bracket. (Figure 66)
At right and left upper corners of water heater
Near fan assembly location
4 screws
(bracket)
9 screws
(cover plate)
Figure 63
4 screws
Figure 64
Figure 65
Figure 66
26. Install the largest O-ring (included in kit) over the water outlet tube and the two smaller O-rings (included in kit)
over the bypass servo tubes. (Figure 57)
27. Install the bracket over the replacement heat exchanger. Push evenly on both sides of the bracket. Attach
with four screws. (Figure 66)
2 screws
2 screws
Figure 62
1 screw
3 screws
Figure 61
WARNING
Failure to correctly assemble the components according to these instructions
could result in a gas leak or explosion.
Install Packings and Bracket
Heat Exchanger
On-Demand Gas Tankless Water Heater Service Manual
48